Agitating means for aerosol spray cans



April 30, 1963 w. MOONAN 3,087,707

AGITATING MEANS FOR AEROSOL SPRAY CANS Filed Feb. 1, 1962 INVENTOR.

Ml/AM MGOA/A/V BY I Nari 7 7 6M United States Patent ice 3,087,707AGITATING MEANS FOR AEROSOL SPRAY CANS William Moonan, Shaker Heights,Ohio, assignor to Sprayon Products, Inc., Cleveland, Ohio, a corporationof Ohio Filed Feb. 1, 1962, Ser. No. 170,320 9 Claims. ((31. 259-29)This invention relates to agitating or mixing devices for aerosolproducts containing pigments or other materials which tend to settle outduring storage.

Aerosol spray cans containing paints, lacquers, enamels and the like aresold in large quantities. These cans contain the required pigments, avehicle composed of appropriate resins, oils, solvents and the like inwhich the pigments are suspended, and a liquefied propellant gas such asdichlorofiuoromethane. Many of them, containing lacquers, enamels,paints and the like formulated to match original factory-appliedfinishes, are used in refinishing or retouching marred appliances,slightly damaged automobiles and for similar purposes where colormatching is of great importance.

In practically all paints, varnishes and lacquers the pigments tend tosettle out during storage and unless the pigments are thoroughly mixedwith the vehicle before the material is applied, the desired color willnot be produced. The problem of settling is particularly severe withaerosol products for the reason that the liquefied propellant gas, whichis necessarily compatible with the remaining constituents of the paint,lacquer or enamel is of very low viscosity and thus acts to thin thevehicle in the spray can and increase the rate of settling as comparedto the rate in conventional paint containers. The different pigmentsused to produce a given desired shade usually settle at diiferent ratesand thus settle in layers of different compositions. For this reasontrue colors cannot be obtained unless substantially all of the pigmentsare very thoroughly mixed in the can. The differential settling effectis accentuated in aerosol containers by the presence of the liquefiedpropellant.

Since the contents of the cans must be maintained under pressure, thecans cannot be opened for the purpose of stirring and mixing thecontents. For this reason, it has been the practice to use agitatorswithin the cans to help break up and mix the settled pigments when thecan is shaken. These have taken the form of relatively large balls oragitators of various shapes With prior types of agitators, however, ithas been necessary to shake the cans containing the agitators forinordinately long times even to approximate good color matching. Theuser frequently fails to shake the can long enough and then when hesprays the contents he does not obtain the desired color and as a resultbecomes an immediately dissatisfied customer.

The reason for the failure of the agitators of the prior art, whichgenerally consist in one or two balls of uniform size and about indiameter, is that the usual aerosol can, since it must withstand aninternal pressure of approximately 70 pounds per square inch, has adomed bottom leaving an annular V-shaped groove at the juncture of thebottom and the side wall of the can. If a ball or other agitator isemployed that is large enough and of sufficient mass to enable it to beshaken loose from and effectively to mix the settled pigments, then theball is too large to remove the pigments from ibis groove. 'If the ballsare small enough to remove most of the pigments from the groove they areordinarily of insufiicient mass to be shaken loose from the settledpigment and are ineffective as agitators,

According to the present invention, an improved and greatly superioragitating or mixing system for aerosol 3,087,707 Patented Apr. 30, 1963spray cans having domed bottoms is provided by disposing within the canone or two agitating elements, preferably in the form of balls, that arelarge enough and of sufficient mass that they can be readily brokenloose from the settled pigment when the can is shaken, in combinationwith several, for example, five to seven, smaller agitating elements,also preferably in the form of balls, that are of such size that theycan clean out most of the pigments from the groove between the domedbottom of the can and the side wall thereof. These smaller elements,however, are of a size so related to the angle of the groove and thesize of the larger elements that they can be engaged by the largerelements and moved through the pigment by the larger elements, even whenthe smaller elements are disposed as deeply as possible in the groove.With this arrangement, thorough mixing of settled solid materials withthe remainder of the contents of the cans can be obtained by shaking thecans. The mixing is much more thorough and much faster than withconventional agitators. The result is that with paints, lacquers,enamels and the like excellent color matching can be obtained by shakingthe cans for a comparatively short time.

A preferred form of the invention is illustrated in the accompanyingdrawings in which:

FIGURE 1 is a side elevational view, partly in section, showing anaerosol spray can embodying a preferred form of the invention andillustrating somewhat diagrammatically the manner in which pigments orother solids settle to the bottom of the can;

FIGURE 2 is a fragmentary sectional view showing the manner in which theagitators engage each other in the groove at the base of the can; and

FIGURE 3 is a perspective on the same scale as FIG- URE 1 showing aplurality of agitator balls in the groove at the base of the can.

Asshown in FIGURE l of the drawings, the invention is adaptable to atypical aerosol can 10 having a cylindrical side Wall 11 and an upwardlyconvex or domed bottom 12 The bottom is domed in order to give itstrength to withstand the pressure within the can which may be of theorder of 70 psi. The bottom 12 is crimped and soldered to the can in aconventional manner as indicated at 13. The convex bottom intersects theside wall at an angle of about 60 .to form an annular V-shaped groove14.

The upper end of the can 11 is reduced in diameter as shown and has anopening which is closed by a conventional closure cap 15 which supportsa valve 16 that may be of any conventional construction. In the form ofthe invention shown, the valve has an actuating flap 18. When this isdepressed by the user the valve is opened and the pressure of thepropellant fluid within the can causes the contents of the can to flowupwardly through a dip tube 19, which is preferably composed of aflexible plastic, to the valve 16 and finally to be discharged from aspray orifice 20. The dip tube 19 projects downwardly and is preferablycurved toward one side of the can as shown.

As shown in FIGURE 1 of the drawings, the can when sold is filled to alevel near the top of the can with the material 25 to be dispensed. Inthe case of a pigmented paint, lacquer, enamel or the like, the contentsof the can consist of a liquefied propellant gas, such asdichlorodifluoromethane, and the paint, enamel or lacquer to bedispensed, which in turn consists of appropriate pigments suspended in avehicle that includes the usual resins, solvents, oils and the like.Inasmuch as the. liquefied propellant is miscible with the vehicle inwhich the pigment is suspended, the liquid portion of the contents ofthe can is of very low viscosity, and accordingly it is for allpractical purposes impossible to prevent settling of the pigments duringstorage. In fact, for some types of materials settling takes place sorapidly that if it is desired to maintain the desired composition of thematerial being sprayed, the can should be shaken every few minutesduring use.

In any event, while the can is in its normal upright position on theshelf of a dealer or in the possession of the ultimate user, thepigments at least in part settle out, as indicated at 26 in FIGURE 1.The end 30 of the dip tube is preferably slightly above the level of thesettled pigments, as shown. Ordinarily, mixtures of pigments areemployed to obtain desired colors and shades. These pigments generallyhave different rates of settling. Pigments having a higher rate settlein the groove 14 in greater proportion than the remainder of thepigments and the pigments become somewhat stratified in settling.Therefore, unless most of the settled pigments are scoured out of thegroove 14 and mixed with the liquid in the can, the desired color simplywill not be sprayed.

According to the present invention, effective agitation and mixing ofthe contents of aerosol cans is obtained by employing one or morerelatively large agitating elements shown herein as balls 28 incombination with several, preferably five to seven smaller agitatingelements shown herein as balls 29. Ordinarily, one large ball issufficient, but two or more may be employed if desired. The large ballor balls 28 must have sutficient mass to enable it to be broken loosefrom the settled pigments by shaking the can. For conventional aerosolcans, such as the six to sixteen ounce cans that are widely used, adiameter steel ball is a satisfactory large agitating element. Balls ofthis size can be shaken loose from the settled pigment without muchdifficulty. If substantially smaller balls are employed, however, it maybe impossible to shake them loose. It will be noted from FIG- URES 1 and2 that balls of this size are held a substantial distance away from thebottom of the groove 14 by engagement with the domed bottom 12 and theside wall 11 of the can. Hence, balls of this size when used alone donot perform an adequate mixing job.

This deficiency is corrected in accordance with the present invention bythe smaller balls 29. These preferably take the form of conventionallead BB shot. Such shot have a diameter of about 0.18 inch and arereadily available at low cost. While BB shot by themselves haveinsuflicient mass to act as adequate mixers or agitators they workeffectively in combination with one or more larger balls or agitators.The reason for the effectiveness of the combination will be evident froma consideration of FIGURE 2 of the drawings. As there shown, the smallerballs or shot 29 go deep enough into the groove so that only a smallamount of pigment can remain in the groove if the balls are forcedaround near the base of the groove. At the same time, the balls arelarge enough so that they project above the lowest position that can betaken by the larger ball 28. When the can is shaken the larger ball notonly disrupts and breaks loose the solidified pigment but also strikesthe smaller balls and moves them around through the pigment, thussecuring superior agitation and mixing of the material. It is to benoted that, as shown particularly in FIGURE 3, a lower surface of thelarger ball engages an upper surface of a smaller ball and thus tends toforce the smaller ball down into the groove where it will do therequired job.

In operation, the pigments or other solid materials are suspended in theliquid when the cans are filled and, therefore, the balls simply rolldown the domed bottom 12 and remain disposed in the groove in thepositions such as shown in the drawings during the time that the goodsare in upright position as they normally are on a shelf. After someperiod of storage, the pigment or other solid material in the cansettles, as shown diagrammatically in the drawing. The first few shakesof the can serve to break loose the larger ball or balls from thepigment, and continued shaking causes both the large and small balls tobe moved through the pigment and to agitate the contents of the can. Theengagement of the larger balls with the smaller balls causes the smallerballs effectively to scour out substantially all of the settled-outmaterial from the bottom of the groove. While the smaller balls do notreach entirely into the bottom of the groove, it appears that thecurrents they create in the liquid contents of the can cause the liquidto scour or wash substantially all of the pigments or other solids outof the groove, even though an appreciable amount of pigment cannot becontacted directly by the balls. This hitherto unobtainable result hasbeen demonstrated not only by the excellent color matching obtained withcans embodying the present invention, but also by tests in which aerosolcans containing pigmented materials have been allowed to settle forperiods of time up to several months, the cans shaken, the contents ofthe cans discharged and the cans cut open and examined. Theseexaminations have shown substantially complete removal of the solidsfrom the grooves with cans embodying the present invention. Generallyspeaking, tests show that with average materials brisk shaking for about15 to 30 seconds is sufiicient properly to mix the pigments, whereaspreviously known agitators require at least about 4 times as muchshaking for the same materials allowed to stand for the same periods oftime, and with some materials, conventional agitators are simply unableto do a satisfactory job in any reasonable period of time. With somematerials, such as certain metallic pigments, it may be desirableperiodically to shake the can as the spraying operation is carried out.The contents of the can are sprayed in normal fashion. If the can isreplaced on a shelf after partial spraying of its contents the agitatorballs simply take their usual positions in the groove and are ready toagitate and mix the contents of the can again when the can is shakenagain preparatory to further use.

According to the preferred form of the invention, one steel ball ofabout diameter is utilized in conjunction with five to seven lead BBshot. The sizes and materials used for the balls may vary withinreasonable limits, and the number of balls employed may also be varied.However, the larger ball must be big enough so that it can be brokenfree from the settled material without too much difiiculty, and thesmaller balls should be as small as possible to enable them to penetrateinto the groove as far as possible but at the same time they must belarge enough so that the large ball and the small balls overlap Whenboth of the balls are disposed in the groove 14, as shown in FIGURE 2.The overlap insures that the small balls can be struck by the largerball when the smaller balls are as deep in the groove as they can go.Also, they must not be so small that they can become jammed or stuck inthe groove and thus made ineffective.

While the invention has been explained with particular reference to itsuse in conjunction with aerosol spray cans containing lacquer, enamel,paint or the like, it will be understood that the invention is alsouseful in connection with aerosol sprays embodying other materials thatare apt to settle out during storage of the cans.

Those skilled in the art will appreciate that various changes andmodifications can be made in the preferred form of the inventiondisclosed herein without departing from the spirit and scope thereof.The essential characteristics of the invention are defined in theclaims.

I claim:

1. In an aerosol spray can having a cylindrical side wall and a domedbottom secured to the side wall and defining with said side wall anannular V-shaped groove,

said can containing a liquefied propellant gas and a material to besprayed comprising a suspension of solid particles subject to settlingduring storage of said can,

means for agitating and mixing the contents of said can comprising arelatively large agitating element disposed within said can, saidelement being of suificient mass to be broken loose readily from saidsettled solid particles when said can is shaken and being of such sizethat it is supported by engagement with said domed bottom and said sidewall at a distance spaced substantially from the bottom of said groove,and

a plurality of relatively small agitating elements of such size thatthey extend within said groove substantially farther than saidrelatively large element when in engagement with said domed bottom andsaid cylindrical side wall,

said relatively small elements being engageable by said relatively largeelement when both large and small elements are disposed as close to thebottom of said groove as possible, and

said relatively small elements being adapted to cause the removal ofsubstantially all of said settled solid particles from said groove whensaid can is shaken.

2. A device according to claim 1 wherein the agitating elements areballs.

3. A device according to claim 2 wherein the larger element has adiameter about twice the diameter of the smaller element.

4. A device according to claim 3 wherein the larger element is a steelball having a diameter of about inch and the smaller elements are ballshaving a diameter of about 0.18 inch.

5. A device according to claim 4 wherein the smaller elements are BBshot.

6. A device according to claim 5 wherein only one steel ball is employedand from five to seven BB shot are employed.

7. A device according to claim 6 wherein said side wall and said bottomintersect at an angle of approximately 60 degrees.

8. In an aerosol spray can having a cylindrical side wall, a domedbottom secured to the side wall and defining with the said wall anannular V-shaped groove, the walls of which intersect at an angle ofapproximately 60 degrees,

a discharge valve at the top of the can and a flexible dip tubeextending from said discharge valve partially into said V-shaped groove,

said can containing a liquefied propellant gas and a pigmented materialto be sprayed, the pigments in said material being subject to settlingduring storage of said can,

means for agitating and mixing the contents of said can comprising arelatively large ball disposed within said can, said ball being ofsufiicient mass to be broken loose readily from said settled pigmentwhen said can is shaken and being of such size that it is supported byengagement with said domed bottom and said side Wall of said can at adistance spaced substantially from the bottom of said groove, and

a plurality of relatively small balls of such size that they extendwithin said groove substantially farther than said relatively large ballwhen in engagement with said domed bottom and said cylindrical sidewall,

said relatively small balls being engageable by said relatively largeball when both large and small balls are disposed as close to the bottomof said groove as possible, and

said relatively small balls being adapted to cause the removal ofsubstantially all of said settled pigment from said groove when said canis shaken.

9. A device according to claim 8 wherein the large ball has a diameterof about inch and the small balls have a diameter about one half thediameter of the large ball.

References Cited in the file of this patent UNITED STATES PATENTS2,168,086 Butler Aug. 1, 1939 2,168,093 Osgood Aug. 1, 1939 2,332,701Dowsett Oct. 26, 1943 2,580,132 Seymour Dec. 25, 1951 FOREIGN PATENTS218,572 Australia of 1957

1. IN AN AEROSOL SPRAY CON HAVING A CYLINDRICAL SIDE WALL AND A DOMEDBOTTOM SECURED TO THE SIDE WALL AND DEFINING WITH SAID SIDE WALL ANNULARV-SHAPED GROOVE, SAID CAN CONTAINING A LIQUEFIED PROPELLANT GAS AND AMATERIAL TO BE SPRAYED COMPRISING A SUSPENSION OF SOLID PARTICLESSUBJECT TO SETTLING DURING STORAGE OF SAID CAN,